List of top Electronics and Communication Engineering Questions on Signals and Systems

What is the Z-transform of a unit impulse function $\delta[n]$?

The signal-to-noise ratio (SNR) of an ADC with a full-scale sinusoidal input is given to be 61.96 dB. The resolution of the ADC is ___________ bits (rounded off to the nearest integer).

For the two port network shown below, the [Y]-parameters is given as \[ [Y] = \frac{1}{100} \begin{bmatrix} 2 & -1 \\ -1 & \frac{4}{3} \end{bmatrix} \text{ S}. \] The value of load impedance $ Z_L $, in $ \Omega $, for maximum power transfer will be ___________ (rounded off to the nearest integer).

Let $x_1(t) = u(t+1.5) - u(t-1.5)$ and $x_2(t)$ is shown in the figure below. For $y(t) = x_1(t) x_2(t)$, the $\int_{-\infty}^{\infty} y(t)dt$ is ___________ (rounded off to the nearest integer).

Let X(t) be a white Gaussian noise with power spectral density $\frac{3}{2}$ W/Hz. If X(t) is input to an LTI system with impulse response $e^{-t}u(t)$. The average power of the system output is ___________ W (rounded off to two decimal places).

A transparent dielectric coating is applied to glass ($\epsilon_r = 4, \mu_r = 1$) to eliminate the reflection of red light ($\lambda_0 = 0.75 \mu m$). The minimum thickness of the dielectric coating, in $\mu$m, that can be used is ___________ (rounded off to two decimal places).

The frequency of occurrence of 8 symbols (a-h) is shown in the table below. A symbol is chosen and it is determined by asking a series of "yes/no" questions which are assumed to be truthfully answered. The average number of questions when asked in the most efficient sequence, to determine the chosen symbol, is ___________ (rounded off to two decimal places).